Since wireless communication technology is highly developed, mobile phones are becoming increasingly light and easy to hold. Nowadays, most people use mobile phones to communicate with others. Therefore, the mobile phone has become a necessary electronic device in people's lives.
Due to the popularity of mobile phones, mobile phone manufacturers are working extremely hard to increase mobile phone functions in order to satisfy various requirements desired by users. For example, some of the mobile phones provide PDA functions, such as address book, calendar, minutes and/or agendas. Some mobile phones provide electronic games therein for the users to play during their idle time. Further, some mobile phones have digital cameras thereon so that users can take beautiful pictures to share with their friends.
However, a current mobile phone generally has a size smaller than that of a palm, and especially, a smaller mobile phone only has a size almost similar to that of an egg. Therefore, the surface area for the keyboard and display on a mobile phone is limited. Integrating all the foregoing functions into such a small mobile phone is difficult. To increase the available surface area, some mobile phones are designed to dispose the keyboard and the display respectively on two electronic modules, which are connected to each other via a sliding mechanism, so as to construct, for example, a slide cell phone including a sliding keyboard and a sliding display.
In the meantime, some of the mobile phone manufacturers design a keyboard module, which has a key arrangement similar to that of a standard QWERTY keyboard, to prevent users from changing their input habits and thus to facilitate their typing speed, and also utilize a display with a landscape view for user to type like using a computer. However, the quasi QWERTY keyboard on the mobile phones is not suitable to be used for dialing telephone numbers. Therefore, some of the mobile phone manufactures further design a PDA mobile phone with two keyboard modules. The PDA mobile phone with two keyboard modules normally adopts three electronic modules stacked together for respectively disposing the display, the quasi QWERTY keyboard and the telephone keyboard thereon, and includes different sliding modules coupling the three electronic modules together so as to enable the display, the quasi QWERTY keyboard and the telephone keyboard to be opened in different directions.
However, while the mobile phone is getting small, the mobile phone with three stacked electronic modules is not only increased in size and weight but also inconvenient to be carried. Therefore, there is a need to reduce the thickness of the mobile phone, which is able to be opened in different directions, such that the mobile phone could be reduced in size while providing various input functions.